This invention relates to auxiliary or storm windows and more particularly to a window which can be inexpensively installed on the inside of prime windows.
It has been estimated that there are 22 billion square feet of single glazed windows in industrial and commercial buildings in the United States. Heat is lost through these windows by conduction through the glass and by infiltration or leakage of cold air around the cracks of the movable sash or sections of the windows. Providing an auxiliary closure for such windows is particularly difficult because the windows are of various sizes and styles and because some of the windows are particularly large.
The prior art window weatherization techniques have not been completely satisfactory. Clear plastic film has been used because it is inexpensive and easy to install. This film has a very short life, low efficiency, poor appearance and the window cannot thereafter be operated without destroying the film. Plastic panels also have been permanently installed on windows. These have the advantage of inexpensive installation and provide good efficiency. However, they cannot be operated. Also, there is a high waste factor in installation because a full plastic sheet must normally be used in weatherizing one window.
Glass storm windows have been in use for a number of years. They are very expensive, dangerous, provide only average efficiency and present installation problems, particularly where they must be custom made to fit odd shaped windows. One such storm window is illustrated in U.S. Pat. No. 2,745,485 to Etling. Etling discloses a storm window which may be adapted to window casings of various dimensions, however these storm windows are placed within rather than over the window casing, thus requiring the installer to fit the window to rather precise dimensions.